Triad(redirected from lethal triad)
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triadsee DYAD AND TRIAD.
in music, a chord whose tones are arranged, or may be arranged, in thirds.
The term “triad” encompasses four chords that differ in structure and expressive quality. The division of a perfect fifth into two unequal thirds produces the two main types of triad: major (a major third plus a minor third) and minor (a minor third plus a major third), both of which are consonant. The major triad coincides with the first six tones of the harmonic series and, possibly because of this “natural” character, has a bright, joyful coloration. The minor triad opposes the “natural” order and has a dark, mournful sound. Consonant triads were the harmonic foundation of the major and minor tonal system that prevailed from the 17th through the 19th century. Major and minor triads form the basis of the two main tonalities of European music—major and minor. Consonant triads have remained significant even in 20th-century music.
Two triads composed of equal intervals are particularly important: the augmented triad, comprising two major thirds, and the diminished triad, comprising two minor thirds. Because they violate the consonance of a perfect fifth, both lack stability, force, and consonance, especially the diminished triad, which contains the dissonance of a diminished fifth. For this reason, their application is limited.
IU. N. KHOLOPOV
a term denoting the three-stage cycle, or triadic progression, of being and thought. As a theoretical concept, the triad was studied by Plato and the Neoplatonists, and particularly by Proclus. The triad forms the basic dialectical principle of development in the works of the German classical idealists—J. G. Fichte, F. von Schelling, and especially G. Hegel. According to Hegel, for whom the triad is also a means of constructing a philosophical system, all development consists of three stages: thesis, antithesis, and synthesis. The antithesis negates the thesis, and the synthesis in turn negates the antithesis. The synthesis, however, preserves and combines within itself certain properties of the preceding stages of development.
While accepting the principle of the triadic development of being and knowledge, the founders of Marxism rejected the Hegelian premise that the subject of triadic development is the absolute idea. In dialectical materialism, the concept of development must be understood not in terms of triads but as a process of contradictions—that is, a process involving the sublation of contradictions at a higher level of development by means of negation and the negation of the negation.
V. F. ASMUS
CIA(1) (Confidentiality-Integrity-Availability) A widely used formulation of the INFOSEC mission of the U.S. military. Also known as the "Classic Triad," the three concepts fail to include important problems intuitively seen as breaches of security, forgeries or counterfeits, mislabeling of data and problems of data usability. See Parkerian Hexad.
(2) (CiA) See CAN bus.